An electric double-layered capacitor uses electric energy supplied from an electric double layer formed at an interface between a pair of electrodes as a cathode or an anode made of an activated carbon and an electrolyte. A small coin-type electric double-layered capacitor is characterized by high energy density, lightweight, and little environmental burden. There are rapidly increasing demands for electric double-layered capacitors as a memory backup
power source for portable apparatus such as a mobile phone or a digital camera. In particular, the electric double-layered capacitor is widely employed in a memory backup of a digital GSM mobile phone which is widely used in Europe, Asia, Africa, or Middle and Near East in view of environmental responsiveness.
In addition, it is desired that a lithium secondary battery to be used in a high functionally mobile phone be replaced by an environmentally friendly electric double-layered capacitor formed of carbon and a metal container only.
The electric double-layered capacitor, which does not include a chemical reaction in its charge-discharge mechanism, can be charged or discharged at a large electric current, as compared with a lithium ion battery. However, reduction in internal resistance of the electric double-layered capacitor has been desired in order to further improve charge-discharge characteristics of the capacitor.
In addition, a solder reflow method involving heating solder in a reflow furnace at a high temperature of about 250 to 260° C. to melt solder has been recently employed as a method of connecting the electric double-layered capacitor to a substrate.
Various attempts including improvement of a material for a separator or a gasket have been made as means for solving a problem due to the reflow heat to thereby improve heat resistance of the capacitor.
Patent Document 1: JP 6-176971 A
Patent Document 2: JP 8-298232 A
Patent Document 3: JP 2004-14989 A
Patent Document 4: JP 2005-347100 A